新生兒常見的器官問題就是心臟缺損, 光是美國每年就有 35,000位新生兒發現心瓣膜缺陷, 發生機率是每250人就有1人

常見的是心瓣膜過於狹窄, 血液不易順利通過或堵塞, 無法手術治療, 而是用機械, 人心捐贈, 或者豬心瓣膜三種方式取代, 然而這三種方法壽命有限, 新生兒成長過程中須進行多次手術

紐奧良舉辦的美國心臟學會發表, 蒐集新生兒出生臍帶血幹細胞, 種在心瓣膜上, 可以培育出HLA-TYPED符合的心瓣膜

Stem Cells from Umbilical Cord Blood Used to Grow Heart Valves

In what is called a concept study, cardiologists at the University Hospital of Munich collected umbilical cord blood at birth and then froze it to preserve the cells. After 12 weeks, they harvested the stem cells, seeded them onto eight biodegradable heart valve scaffolds and grew them in the laboratory. Upon examination with electron microscopes, researchers could see the cells had grown into the pores of the scaffolding and formed a tissue layer. Biochemical examination indicated that the cells had produced important elements of the “extracellular matrix,” the portion of body tissue that functions outside of cells and is essential to tissue function and structure. Compared with human tissue from pulmonary heart valves, the tissue-engineered valves had 77.9 percent as much collagen (the main protein in connective tissue); 85 percent as much glycosaminoglycan (a carbohydrate important in connective tissue); and 67 percent as much elastin (a protein in connective tissue). The valves also contained desmin (a protein in muscle cells), laminin (a protein in all internal organs), alpha-actin (a protein that helps muscle cells contract) and CD31, VWF and VE-cadherin (components of blood vessel linings).

Over time, the scaffolds will dissolve, leaving behind a fully formed structure made from the cells, explained cardiac surgeon Ralf Sodian, who led the study. “The basic idea is to implant something living, functional from your own cells which will integrate into the surrounding tissue with the potential to grow,” Sodian said. “Tissue engineering provides the prospect of an ideal heart valve substitute that lasts throughout the patient’s lifetime and has the potential to grow with the recipient and to change shape as needed.”

Sodian cautioned that, while the technique shows promise, researchers need to work out several issues before they can attempt it in people. The next step is test the procedure by implanting these tissue-engineered heart valves into young lambs and watching to see how they grow and function over time. Sodian says he hopes to begin these experiments next year.

Although stem cells from human embryos are more versatile, since they are able to form any of the roughly 210 cell types found in the body, stem cells from umbilical cord blood have the potential to form many kinds of cells that can repair or replace damage to organs of the body. And, since the umbilical cord cells are not derived from human embryos, they don’t raise the ethical objections, such as those that led President George W. Bush to limit federal funding for embryonic stem cell research. However, reports are that President-elect Barack Obama plans to possibly undo the Bush restrictions on embryonic stem-cell research by executive order once he takes office on January 20.

The study findings were presented at the American Heart Association’s annual scientific sessions in New Orleans.